The superiority of nephron-sparing surgery over radical nephrectomy in preserving renal function extends to tumors larger than 4 cm.
Nephron-sparing surgery is the standard of care for small renal tumors, with a traditional cutoff of 4 cm. Whether preservation of renal function is superior with nephron-sparing surgery for larger tumors remains unanswered.
Median age at diagnosis was 60 years. There were 670 tumors in the analysis; half were 4 cm or smaller, 27.3% were >4 cm to 7 cm in size, and 22.7% were >7 cm. Mean follow-up was approximately 42 months in each group.
Among patients with tumors 4 cm or smaller, the mean MDRD GFR loss was 11% in those who underwent nephron-sparing surgery and 30% in those who underwent radical nephrectomy (p=.0001), reported first author Jean-Jacques Patard, MD, PhD, professor of urology at the University of Rennes, France. In addition, among patients with tumors larger than 4 cm, mean MDRD GFR loss was 14% and 21% in those who underwent nephron-sparing surgery and radical nephrectomy, respectively (p=.0001). However, this trend did not persist in patients with tumors larger than 7 cm.
In a multivariate analysis, the use of radical nephrectomy, a preoperative MDRD <60 mL/min/1.73 m2 , and age 60 or older at diagnosis were independent predictors of significant postoperative MDRD GFR loss, said Dr. Patard.
The findings support performing partial nephrectomy when technically feasible for renal tumors up to 7 cm, Dr. Patard said; however, the jury is still out on whether partial nephrectomy remains beneficial in cases of renal tumors larger than 7 cm.